A Tracking Review on Non Arc Melting Processes for Improved Surface Properties in Metallic Materials

Most metallic materials lack the adequate surface characteristics to satisfactorily perform intended service functions. In such instance, the surface properties are modified by altering the chemistry, structure and/topology of the top surface of the surface via modification techniques. There exists wide options of techniques for modifying the surface properties and these are well documented in the literature. However, these techniques have different scientific underpinnings controlling them such that it is difficult to use a single mechanism to characterize the techniques. Arising from this, it is imperative that a holistic understanding of the various processes is provided. Therefore, in this paper, research status on the wide range of non-melting technique for surface modification is presented. The presentation discusses the investigation conducted on the various non-surface melting techniques and provides a comparison across the techniques. Recent developments in these techniques are equally presented. Existing challenges and emerging trends in the field are also highlighted.  . Keywords: coating composition, coating techniques, metallic materials, substrate, surface properties DOI: 10.7176/CMR/13-2-01 Publication date:May 31st 202

Investigation of the Effect of R134a/Al2O3 –Nanofluid on the Performance of a Domestic Vapour Compression Refrigeration System

use of nanoparticles in heat transfer fluids. The study investigated the effect of Al2O3 nanoparticles on the working fluids of a vapour compression refrigeration system (VCRS) when used with refrigerant R134a. The nanorefrigerant was used in the vapour compression system without system retrofit. The system’s performance analyses were carried out via the freeze capacity tests and energy consumption analysis. The outcome showed that the performance of the Al2O3-dispersed nano-working fluid outperformed that of the conventional working fluid mixture. Specifically, the outcome demonstrated that the system with the nanorefrigerant achieved faster cooling, better performance and improved energy consumption. Thus, using Al2O3 nanoparticles in combination with the working fluids of domestic refrigerators was shown to be feasible. Further to this, based on the performance results, it was necessary to find out the very reason behind the improved thermal performance of the nanoparticle dispersed working fluid. This led to the determination of the thermophysical property of the nanolubricant. The results indicate better thermal conductivity and salinity, implying that the nanolubricant has better heat transfer ability than the base oil (Capella D). In addition to this, the results of the viscosity test showed that the presence of the nanoparticles caused a reduction in the lubricant’s viscosity thus portraying a reduction in the energy consumption. However, the pH test results indicate that there may be the need for an improved compressor material selection if the nanorefrigerant will be employed for vapour compression refrigeration purposes in the future

Biogas use as fuel in spark ignition engines

Abstract: This paper reviews the utilization of biogas in spark ignition engines with a view to making a case for it as an efficient substitute fuel for petrol. However, its gaseous nature which accounts for its low volumetric density implies that apart from the basic modification needed to accommodate the fuel, the engine might need further alterations to get the best from this relatively low cost and readily available fuel. Various modes of enhancing performance particularly methane enrichment, prechamber combustion, alteration of ignition parameters, increasing compression ratio and addition of hydrogen to improve performance and emissions were drawn from previous works to validate its efficiency as a viable substitute fuel in SI engines

Effects of Housing Modifications on the Management of Pigs and Growth Performance

Pig industry in Nigeria is an important arm of the livestock sub-sector in the overall agricultural sector. The comfort of Pigs is determined by effective environmental temperature. It combines the effect of air temperature, flooring, and bedding. The aim of this study is to investigate the impact of different intensive housing systems on the feed consumption level, weight gain and welfare of pigs fed with the same feed (diet) under different housing systems for 8 weeks. Nine Pigs were purchased from a reputable commercial farm and were divided into 3 treatment groups, T1, T2 and T3. T1 is a well built pen with cemented wall and floor. T2 is a pen built with bamboo wall, and cemented floor. T3 is built with bamboo wall without cemented floor – bare loamy soil. The Pigs were raised for eight weeks. The feed given and weight gained for eight weeks were recorded and analysed using ANOVA. Considering the consumption levels of all treatments, T2 had the lowest feed intake compared to other treatments. T2 had the highest weight gain while T3had the lowest. It is hereby concluded that T3 presented the best result as regards feed consumption, cost of construction and ease of management. Although it presented the lowest weight gain which is attributable to the initial weight and tipping of the feed trough (feed wastage). However, feed wastage can be minimized by using firmer feed trough

Metallurgical and Corrosion Property of Additive Manufactured Titanium Alloy-Ti6Al4V

Additive manufacturing (AM) is an important manufacturing technology that has changed the way products are designed and manufactured. Laser Metal Deposition (LMD), an AM technology, has the capability of producing components using a 3-Dimensional CAD model, through a layer by layer formation process just like any other AM technology. In this study, the influence of the scanning speed on the corrosion property of Titanium alloy-Ti6Al4V using LMD process was investigated. The scanning speed varied between 0.02 m/s and 0.14 m/s while other processing parameters were kept constant. The electrochemical corrosion test was conducted in sodium chloride (NaCl) solution. The result revealed that the corrosion resistance property was found to increase with the scanning speed

Process Parameter Influence on Tensile Property of Friction Stir Processed Al/Ni-Fe Composite

Friction stir processing (FSP) is a solid-state processing technique that has proven to be an efficient surface modification process for producing aluminium matrix composites (AMCs). However, practical challenges still occur during the processing of AMCs even though extensive progress has been made in recent years. In the present study, the influence of FSP process parameters on the tensile property of Al-Ni-Fe composite has been investigated. The process parameters studied were rotational speed and advancing speed. The rotational speed varied between 600 and 1000 rpm while the advancing speed varied between 70 and 210 mm/min. The rotational speed was kept constant at each setting and the advancing speed varied. Other processing parameters were kept constant throughout the experiments. The results were compared with those of the base metal (Al). The results showed that the tensile strength decreased as the advancing speed increased. The highest tensile strength was obtained at a rotational speed of 1000 rpm and an advancing speed of 70 mm/min

Environmental sustainability : multi-criteria decision analysis for resource recovery from organic fraction of municipal solid waste

Abstract: Landfills within the City of Johannesburg (CoJ) are running out of airspace. To slow down airspace consumption rate, waste discharged at these landfills must be minimised, and where possible recover useful resources. A multi-criteria decision tool, the Analytical Hierarchy Process (AHP) was employed to appropriate technologies for fruit and vegetables waste discharge at Robinson Deep landfill. The goal of the approach is environmental sustainability. Pairwise comparison of four criteria and four technology alternatives were investigated. Data used were retrieved from a research group and consultations with waste to energy experts. Of the four technology alternatives, anaerobic digestion (AD) is the most preferred. Incineration technology has 49.42% preference to AD because it is perceived to reduce the bulkiness of waste discharged at the landfill. Composting has 25.24% preference to AD and it is believed to encourage home management of waste. Consistency ratio for all pairwise comparison was less than 0.1

Evaluation of a hybrid solar power system as a potential replacement for urban residential and medical economic activity areas in southern Nigeria

A hybrid solar power system (HSPS) is an alternate method of supplying electricity that can reduce fuel usage while maintaining power supply security. In this study, the efficiency of HSPS, which consists of Grid Supply (GS), Diesel Power Generation (DPG), Solar-Photovoltaic (SPV), and Battery Storage (BS) systems, was evaluated in two economic activity areas (EAAs) in Southern Nigeria. The cross-sectional research design was used, and the research was based on Behera's energy-led growth theory. Urban-residential and Health were the EAAs considered and chosen using a stratified random sample technique. Southern Nigerian states of Oyo and Lagos provided the samples, which were combined and used for the study. Electricity consumption was calculated using electricity load demand for the two EAAs from 2008 to 2017. For each EAA, an Integrated Renewable Energy Mini/Microgrid Model (IREMMM) based on power load demand and solar irradiation was constructed. Levelized Cost of Electricity (LCOE) (/kWh), and Net Present Cost (NPC) (M) were calculated for one hybrid configuration, SPV-DPG-BS-GS, and two standalone configurations, DPG and SPV-BS. Configurations with SPV integrated had lower LCOEs than DPGs in both EAAs. In Southern Nigeria, solar PV combinations with battery storage provided the highest performance for a hybrid power system. In the medical contexts, a hybrid power system achieves higher overall performance

Bioremediation: Data on Biologically-Mediated Remediation of Crude Oil (Escravos Light) Polluted Soil using Aspergillus niger

This article presents data on Aspergillus niger effects on the biologically-mediated remediation of soil polluted by raw and treated crude oil (Escravos Light blend). Absorbance of different concentrations of polluted soil samples (5% and 8% w/w) and types (raw and treated), for simulating different onshore crude oil spill, were obtained from the Aspergillus niger inoculated samples using ultra violet-visible (UVVis) spectrophotometry. This measurement was carried out for each sample at selected intervals for the 30-day measurements. The bioremediation data, presented in the article, were subjected to descriptive/analytical statistics of probability density functions and goodness-of-fit test-statistics for dataset-detailing and dataset-comparisons. Information details from these data of biologically-mediated remediation of crude oil polluted soil are useful for furthering research on bioremediation kinetics such as hydrocarbon content analyses, crude oil pollutant removal performance, biodegradation rate parameter and biostimulant efficiencies by the Aspergillus niger effects on the different concentrations of polluted soil

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London